chore: bump workspace to 1.9.0 + CHANGELOG

Workspace version goes from 1.8.1 → 1.9.0. Internal crate deps that
carry an explicit version (wfe-buildkit-protos, wfe-containerd-protos,
wfe in wfe-deno) are bumped to match.

CHANGELOG.md documents the release under `## [1.9.0] - 2026-04-07`:

* wfectl CLI with 17 subcommands
* wfectl validate (local YAML compile, no round-trip)
* Human-friendly workflow names (instance sequencing + definition
  display name)
* wfe-server full feature set (kubernetes + deno + buildkit +
  containerd + rustlang) on a debian base
* wfe-ci builder Dockerfile
* /bin/bash for run scripts
* ensure_store_exists called on host start
* SubWorkflowStep parent data inheritance
* workflows.yaml restructured for YAML 1.1 shallow-merge semantics

wfe-deno/Cargo.toml

@@ -9,7 +9,7 @@ description = "Deno bindings for the WFE workflow engine"
 
 [dependencies]
 wfe-core = { workspace = true, features = ["test-support"] }
-wfe = { version = "1.8.1", path = "../wfe", registry = "sunbeam" }
+wfe = { version = "1.9.0", path = "../wfe", registry = "sunbeam" }
 deno_core = { workspace = true }
 deno_error = { workspace = true }
 tokio = { workspace = true }